LSE Politics and Economics or QUB Chemical Engineering

I have an offer for the former, but after significant thought and concern for my future career, I have applied and received an offer in clearing for the latter.

I am very interested in politics, however I believe I would be more well suited to mathematical/STEM degrees (I don't believe the joint LSE degree provides enough quantitative content to open the door for quantitative economic related careers)
I am also unsure on whether the LSE degree will provide me with good career opportunities.
The average salary for LSE politics graduates is 30k after a year and 42.5k after five years. The economics salaries are obviously a lot higher however with my joint degree I assume the earnings would be a lot closer to the politics data than those with economics degrees.
QUB Chem Engineering grads make 28k after a year, and chemical engineering graduates at similar Russell Group unis make roughly the same that LSE students do after five years (there is no data after one year on Discover Uni for NI courses).
Despite these similar salaries, I believe the fact that Chemical engineers would find employment in much cheaper areas like NI, compare to LSE grads who almost always work in London, means going to QUB may be more promising for earnings.
This, combined with the lower tuition fees for Ni students at QUB and my desire to work in Northern Ireland after uni, means I am tempted to opt for the clearing choice, although I know how big of a decision it is to turn down the other course.